// Press Shift twice to open the Search Everywhere dialog and type `show whitespaces`,
// then press Enter. You can now see whitespace characters in your code.
public class Main {
    public static void main(String[] args) {
    MobileTelephone m= new MobileTelephone();
    SIM s1=new SIMOFChinaMobile();
    m.useSIM(s1);
    m.print();

    SIM s2=new SIMOFChinaUnicom();
    m.useSIM(s2);
    m.print();
    }
}